SIO25: Lawrence Krauss - The Greatest Story Ever Told

Transcript

This transcript was generated automatically and may contain errors — the audio is the record.

0:00:29 Thomas: Hello and welcome to Serious Inquiries Only. This is Episode 25, and I'm your host, Thomas Smith. As you already no doubt know, I'm so excited to bring you Lawrence Krauss today. We had a great interview. It was really fun. I could ask Lawrence Krauss questions forever, really, but unfortunately he only had a limited amount of time, but because otherwise I would have just extended into the far reaches of our universe with the interview. But that being said, it's still, it was great. I got pretty much all the questions I had ready answered, and that was really good, as the best part of my job is the fact that I got to have a list of questions for Lawrence Krauss to answer, and he answered them. So there's nothing more to say. Buy the new book that's coming out.

0:01:15 Thomas: I think it'll be tomorrow. The greatest story ever told so far. I have a link in the show notes. And with that said, let's go over to Lawrence Krauss.

0:01:34 Thomas: Joining me right now is someone I am so excited to have on the show and speak to for the first time, Lawrence Krauss. How are you doing?

0:01:41 Lawrence: I'm doing very well, thank you. It's nice to be talking to you and virtually together with you.

0:01:47 Thomas: A couple of virtual particles, no, not really. You've got a new book coming out, it's called The Greatest Story Ever Told So Far, and it's got a subtitle of Why Are We Here. Immediately, in my mind, what catches my eye is the fact that you've got another why question in there.

0:02:06 Thomas: And I know normally you've got a bit of a distaste for why questions, did it, did somebody sneak that by you, or is, yeah, yeah, yeah,

0:02:06 Lawrence: I think I kind of noticed what the subtitle was before It was printed. But no, I think, look, colloquially we use why questions all the time. But as I said, we just have to understand that every why question is really a how question. But the reason that's there is in some sense the same reason I put it in my last book in a different question, is that these why questions have been usurped by the world's religions to to suggest that they're the resolutions of these fundamental transcendental questions about why are we here, why is there something rather nothing, can be resolved in those ways. And and and the point is that to address those questions, the questions we want to ask which are why, why, we have to understand the how. And that science does address them. And ultimately, really, in this case, resolves the why question by saying, you know, why are we here?

0:03:02 Lawrence: And the answer is, there's no reason. It's a remarkable cosmic accident. That is an amazing story. In fact, the greatest story ever told so far. I

0:03:12 Thomas: Stepping back, would you mind with just a general question about the book? What is the overall goal in writing it? Who you trying to reach? You've already touched on it a little bit, but just to cover that general base. There Sure.

0:03:24 Lawrence: Mean, I try and reach as broad an audience as I can to convey the wonder and beauty of the universe and also provoke people to ask questions and think about their place within the cosmos in a new way. And and and this book, he sort of takes off where, from my last book left off in a way. The last book, The Universe Of Nothing, you know, did address this question, why is there something rather nothing, how could you create a universe from nothing.

And then, but the question is, when you have a universe, how can you create the matter we see in, and the universe we live in. And there, once again, just like my last talk about the revolutions and our understanding of the universe on the largest scales in the last 40 years, this book book addresses the revolutions in our understanding of universe on the smallest scales in the last 40 years, although it starts 2 000 years ago.

And and those revolutions have been remarkable and have changed completely our perspective and shown that the universe we experience is really in some sense an illusion, and that even the universe we live in, the laws of physics are not designed

0:03:27 Thomas: Yeah.

0:04:19 Lawrence: For our existence, that that that the fundamental laws of physics wouldn't even, in fact, allow our existence at some level if it weren't for an accident, when a field froze in a certain configuration in the early history of the universe that allowed the forces we feel to be the way they are and the particles we were made of to have the properties they have. And it had it frozen in a different way, we wouldn't be here. So it is an accident, like, as I allude to in the book, like, like ice crystals on a window in the winter morning freeze in a certain direction, but that there's no more significance to the direction which they freeze then there is significance to the fact that we exist. Yes.

0:04:58 Thomas: You're talking about the Higgs field, right?

0:05:00 Lawrence: The Higgs field.

0:05:00 Thomas: Yeah. I actually was going to ask you a specific question about that because you use that language, you know, an accident that we're here and in reference to the Higgs field being frozen in a certain way. You know, I was wondering, it might be a little bit of an abstract question, but I couldn't help but wonder when I saw that language of an accident and all that, was there a potential result you could have found that wouldn't have been an accident? Like, Like, was there potential, experimental results or theoretical results where physicists would have said this is not an accident? Or is it just is just by definition pretty much anything that led us being here is going to be an accident. Could you take me through that a little bit?

0:05:01 Lawrence: Well, I mean, look, the point is, let's uh say that there's a unique set of laws of physics and they allow for our existence. You could say, is that significant that the the laws of physics are the way they are, and and they couldn't be any other way, and those, and those laws also allow for existence.

Well, you could say that those laws therefore were created for our existence, or you could say, well, it's not that we, that that the universe isn't fine-tuned for us, that we're fine-tuned for the universe. And and that kind of question, in some sense, can't be resolved, but you could have said, but there could be clear evidence of purpose or design. So so you could always interpret any result like that and saying, well, there really is a purpose behind it, but you can't see it.

But you could imagine if there was purpose or design, that there's some explicit evidence of that for, by the way, which there isn't. So you could have imagined of the Large Hadron Collider, that the particles that spewed out would not just spew out, but somehow would come out spelling in Aramaic, I am here,

0:06:32 Lawrence: Or something like that. And then you'd say, oh, well, maybe there's some evidence for something beyond that. But clear evidence of purpose, then you can just say that you can always choose to interpret what we see about the universe as as as having some hidden purpose, but but but that's just redundant and and unnecessary, in my opinion. That's right, we say, you know, I mean, the statement, God works in mysterious ways, is is is really equivalent to saying that, no evidence whatsoever.

0:06:54 Thomas: Yeah, it really couldn't be easier for a creator to make his or herself or itself known.

0:07:10 Thomas: Mysteriously absent ways. Ways. Mysteriously similar to there being no God ways. Anyway, you know, what I love about this book so much, if I didn't say that already, I love the book. It was a great read. One thing I love is the storytelling of it. And I wanted to ask you, was there a point in your career when you decided to kind of take on a bit of a storytelling role? What led led you to that and if there was anybody who served as a particular inspiration to you to start doing that.

0:07:22 Lawrence: Thank you. Well, I think, uh, I don't think there was a sudden moment. I think, in throughout my, my whole life, in some sense, I've been affected by other people's storytelling about science. And one of the reasons I became a scientist, and certainly one of the reasons why I write books, is to return the favor. It was books by people like Isaac Asimov and Albert Einstein and Richard Feynman and others who who got me interested in science in the first place. So it was an evolution of becoming, learning those stories. I think my appreciation for the need for storytelling evolved as I proceeded to do so. So I think of the things that was useful to me as a young person was that I worked at a science museum when I was a kid.

0:08:26 Lawrence: And I think that was really helpful because I began to see the kind of things that would help people, motivate people to begin to think about things, or surprise them. But the aspect, I think, has evolved over time, and my appreciation of storytelling in general as a useful tool to explain things, I think, evolved as I began to write and as I begin myself to tell myself.

And and I think, you know, the very title of this book illustrates my own evolution, some sense, as a writer, um, that this is a story and it's a story worth telling. And and fact that the universe is so remarkable, it's one of the greatest sort of frustrations for me, is that we have this amazing story and so few people know about it, or or or think that they're interested in in it, but they really are, but they just don't know they are. And and and it's just, and and that we're willing to tell other stories, uh, but but unfortunately it's harder to get the story through the noise. And and I'm fortunate enough that now I I have a larger soapbox, so I can try and do that. So maybe I might, maybe my ambitions are company in some sense, my good fortune. Yeah.

0:09:36 Thomas: Speaking of that story being told and maybe being told in some sort of inaccurate ways, one thing that you touch on in the book is an argument I often hear from my religious family and other people like that, which is that Einstein completely rewrote science. And if he rewrote science, then who's to say that there's not some other Einstein just sitting around, probably in in your email inbox waiting to rewrite the rules tomorrow and therefore we can't really trust science scientific or conclusions. What do you say to that argument?

0:10:07 Lawrence: Yeah, well, I mean, you hit the nail on the head. That's that's one of the biggest misunderstandings of science, is that somehow science, scientific revolutions do away with everything that went before them. And that therefore there's no, what we think today will tomorrow be wrong. And therefore, why should we learn what scientists think today? It's just a fad, and there's an objective reality and all of that. And of course, that's exactly how it doesn't work. That's what's true today, what satisfies the test of experiment today, will always be true, whether, even whether, how even if it's subsumed by new results in the future. Newton's laws of gravity are still true for the motions of baseballs, cannonballs, and rocket ships. And whatever we learn about gravity in the future is not going to change that. So there's an objective reality of the world, and our perspective of it can evolve and become richer. But it's not as if the fundamental, that have been validated by experiments, are ever proved fundamentally false.

0:10:59 Lawrence: And I think that's a really important thing, that the story grows and becomes richer, but we don't throw out the old aspects of the story. They become an integral part of the new story.

0:11:09 Thomas: So Einstein didn't disprove Newton, essentially? It's still correct? Those experiments are still correct, even though, is there like a slight amount of error that relativity introduces to common measurements, or is it virtually the same?

0:11:23 Lawrence: Look, Hold the ball up in the air and drop it, and Newton would say exactly what would happen. And you couldn't measure, no matter how hard you tried, essentially, the relativistic corrections to the ball falling. Yes, relativity gives you corrections that are, that as you get closer to the speed of light, those corrections become more significant, but on human scales, they're essentially unmeasurable, which is one of the reasons they're so non-intuitive and it took so long to recognize them. But I didn't disprove Newton, he just, he built, and then Newton said, although he'd meant it facetiously, he said, "I, if I've gotten as far as I have, it's because I've stood on the shoulders of giants," and he said that mostly because he was making fun of a competitor who was a dwarf. But but but but but it's true that when we build on the on the discoveries of those that come before us, and science is progressive that way, and that's why the story does get richer.

0:11:47 Thomas: Yeah.

0:12:13 Thomas: One more on kind of the misinterpretation of this sort of the story you've told. There's another thing you talk about, which is all these woo interpretations of quantum physics being on observers. Could you talk a little bit about that? Sort of like that going on, but I have a feeling that's not quite right. Could you clarify that for us?

0:12:42 Lawrence: Well, Yeah. It's Not quite right. In fact, it's one of the biggest misconceptions about about physics that, I suppose, one bothers me is this. You the fact quantum mechanics is strange and wonderful, and it's about in the new book. But but what it's abused by people who try and use that for their own purposes to somehow say that if you think about the universe, it'll do what you want. Mechanics does say that observers can have an impact on the results of experiments.

That's true at an atomic level, and and you, you the observations you make will impact because the underlying, an electron is doing many things at the same time, it turns out, in quantum mechanics, and when you measure it, you pick out one of the things that it, one of the set of possibilities, and and that fixes it. But but it's not as if thinking about the world is going to change it in any way. You have to act on the world. You have to do experiments to change things. And so this notion that consciousness is a key part of quantum mechanics is irrelevant. And as I say in the book, the obvious example of that is that when you look at scientific papers, you don't ever see that anyone saying what the experimenter was thinking about at the time they did the experiment, know whether it was sex or the meal the next day. That that's never discussed. And if consciousness was really an important part of quantum mechanics, you'd have to say what the, what the experimenter's conscious situation was when they were doing experiment, but you never see it.

0:14:06 Thomas: Yeah, I was trying to wrap my mind around that. So, it's not really an observer in that sense, like it matters what's going on in my brain if I'm looking at it. Is it just the act of the way it can be measured? So, like if we had a robot observer.

0:14:06 Lawrence: Okay.

0:14:21 Lawrence: This case an observer. In this case could be a, could be just an experimental apparatus that clicks. You know, it doesn't, and it doesn't need anyone there to hear the click. And the tree, you know, it doesn's that famous tree that falls in the forest, yeah, it does make the sound whether you're there to hear it or not, yeah.

0:14:22 Thomas: Yeah, right. Right.

0:14:40 Thomas: Well, who knows what the observational apparatus was thinking of? I bet it was probably thinking of sex as well. So maybe that's the key.

0:14:46 Lawrence: Depends. If there's an advanced AI, it might be.

0:14:49 Thomas: Oh, you know, another just really difficult concept that I find so fascinating to think about from your book is this idea that there's not really a medium through which light, light waves travel, in the same way that, you know, sound waves travel through air or water, whatever it is, or a literal wave traveling through water. And so that theory, which I, you know, I think now is at least hundreds of years old, that there's some ether that light travels through. Like that, that makes so much sense why people would say that or would think that to me. And yet it's completely wrong. Is there some, is there a good way to wrap, you Now, one's mind around the fact that light, it doesn't, there isn't anything like that. How does that work?

0:15:32 Lawrence: Well, look, there are two answers to that question. First of all, it is true that light does not need, in principle, a medium to travel. It It's a wave of electric and magnetic fields that travel in empty space. At the same time, there are a lot, you know, there are in fact universal backgrounds that do affect everything, and the Higgs field is one of them. It turns out to not be like exactly like the ether, because it happens to not determine a universally preferred rest frame in the universe, but in some sense, qualitatively, or at least spirit, the the Higgs field, it, that's everywhere in space, is kind of like an ether, because in fact the properties of electromagnetic fields would be different if that Higgs fields was different, and and other particles do do propagate in the presence of that background field and are affected by it.

0:16:20 Lawrence: So the notion that they're invisible fields that somehow determine the nature of what we see is manifest in the universe that we see. However, the really important point, and when you say that there's some universal background field that's invisible that affects everything we see, it sounds a lot like religion, doesn't it? And the point is that, well, that would be true if we just made that claim, but the point is we could test it. And that's the whole point, we, if there's a Higgs field, we, we have to be able to create these Higgs particles, as I say, by spanking the vacuum, and it was a difficult 50 year long effort to do so, but it could have gone wrong. And I, at the time, I thought, in fact, the experiments would come up empty. I thought the Higgs fields were probably not there, and uh, and I was wrong, and I'm happy to say I was right. It was

0:17:05 Thomas: Yeah, I've seen you talk about that. Is that something that predicted because it would have been more fun? Or what was your thinking behind it?

0:17:13 Lawrence: Fun when when people are wrong, especially my colleagues. But uh, um, I thought of it because I actually thought, nate, it was such a sort of slippery solution to a problem in physics that, that I thought nature, it might be a little more, more surprising. Nature usually surprises us, and I thought it might be a little more inventive in that way. And, um, and I was very surprised that this, this strange notion of this invisible background field really was true. And it's great to be surprised, and it is great to be wrong, because it involves learning, and and that changed my attitude towards a lot of things. When the Higgs was discovered, I, I wrote a paper that I never would have written if it hadn't been discovered, about the possibilities of the Higgs. It caused me to think about the universe in new ways, and that's really what I like to convey to people with the book. I want them to think the universe and new ways, have the joy of being surprised and discovering, you know, that that that they're not the center of the universe, how

0:17:15 Thomas: Right, right.

0:18:05 Thomas: This was, of course, discovered in the Large Hadron Collider. Is that right?

0:18:10 Lawrence: Well, well, as Richard Dawkins has said numerous times, and recently we were together in England, that there was, he talked about the Large Hadron Collider, and he claimed that there was a typo in the first copy edit of the book. They called it the Large Hardon Collider. He said he wanted them to keep it, but they didn't.

0:18:30 Thomas: Speaking of, a layperson, I saw the headlines, but I don't know what's going on. Are there any more surprises in store potentially from the Large Hadron Collider? Or has it kind of done what it was set out to do? What's going on with it?

0:18:46 Lawrence: Well, we don't know. That's why they're called surprises.

0:18:49 Thomas: Right. I just mean, is there any More pending results of experiments that...

0:18:51 Lawrence: Well, the Large Hadron Collider was actually designed to do a number of things, and many of us thought it would discover other particles called supersymmetric particles in fact instead of the Higgs particle.

And so it's operating right now at a higher energy and higher intensity, and it'll be be operating for the next 15 or 20 years and um we hope that it will in fact give new evidence as I talk about in the book that if we just discover the Higgs we really don't know what the new direction is that are every time we make a new discovery in physics where there are more questions than answers and and and sure we've discovered this Higgs field but why is the Higs field there, why did it freeze in the way it did, what what physics affected that and and could there be new unification of other forces in nature.

These these questions we need, we we don't come up with the answers by revelation. Revelation has never led to new knowledge, we get come up the answers by experiment. And so the the Large Hadron Collider is one of the greatest potential opportunities for for answering the, or at least giving some us some insight into how to to answer those questions well.

0:19:56 Thomas: So is it a question of trying to get higher and higher energies of particles that it's shooting at each other? What? Yeah.

0:20:03 Lawrence: It's Higher energies.

0:20:04 Thomas: Yeah. Is

0:20:05 Lawrence: Which it has achieved, and then higher intensities just get more data, um, so we can look for rare events that might reveal things to us. And we don't know where where the answer will be, maybe it won't be in the Higgs, maybe we'll have to build a new machine, or maybe maybe some signal from the early universe will give us new insights. Uh, we're looking in all directions, um.

0:20:24 Thomas: The race still on between the Large Hadron Collider and these deep underground detectors that you've talked about to try to detect dark matter? Has anything changed in that race or is it still on?

0:20:25 Lawrence: Absolutely.

0:20:40 Lawrence: The race is still on, and that's what makes it exciting. As you point out, as I point out in the book, that that that we're, another place where these new particles may be discovered is the fact that they may have been produced in the early universe, and the remnants may be the dark matter that dominates the mass of all the galaxies we see in the universe today. So there is this race between the dark matter detectors and and and the Large Hadron Collider, and and we don't know who will win the race.

0:21:04 Thomas: Yeah, I sort of get how... I say get, but I think I kind of understand in a really primitive, un-nuanced way, how one of these underground detectors might detect dark matter, which I believe the theory is that it's pretty much all around us, right? It just doesn't interact with what we're made of. Is that right?

0:21:26 Lawrence: Basically that's it, that the dark, that's which makes the dark matters so exciting, if it's new elementary particle, as we think it is, because that means it's not just out there in the galaxy, but it's here in in, and it's in my room as I'm talking to you, in your room as you talk to me, going right through your body and my body and going right to the earth for the most part without knowing the earth was there, except every now and then, if we're correct, there are very rarely, there's an interaction. In fact, these particles bounce off particles of normal matter very very rarely, if we're right. And we can build detectors, and I'm happy to say about 30 some odd years years ago, I was proposing such detectives, which are now being built around the world to look for these things. It's a long, slow process, and maybe we're wrong, but we'll see.

0:22:07 Thomas: Yeah. And I was wondering how would... So I sort of get that concept, how you would detect it there, really rare sort of interaction between those particles. How would the Large Hadron Collider detect or kind of explain dark matter?

0:22:22 Lawrence: Because in fact, you know, this dark matter was produced in the early history of the universe, and the universe was hot and dense, the Big Bang, we think. And the point is that the Large Hadron Collider creates on very small scales conditions that are reminiscent of, say, the universe when it was about a millionth of a million to the second old, and and so therefore we could create those dark, those particles and those collisions, in principle, in the same way that they were created in the early universe. So so it's by Creating These Well

0:22:48 Thomas: Would they be detectable though? Or would they still be?

0:22:50 Lawrence: Well They they would escape the detector for the most part, probably, but the missing, but they carry energy and so that's the way we we we sort of know their existence, yeah.

0:22:54 Thomas: Hmm. You know, there's mass or energy. Oh, okay. You wouldn't just be like, oh, somebody made a math error. There's, we lost some mass or energy. No, I'm just kidding.

0:23:03 Lawrence: Yeah. Well.

0:23:10 Thomas: What is there a similarity or do dark matter and dark energy have any theoretical kind of relation? Or is it just two things we don't know what are, so we call them dark.

0:23:22 Lawrence: Dark, well, I mean, they, it's true that they both, we we don't know what they are, we call them dark simply because they they don't interact with light as far as we see, but they're vastly different. Dark matter is something that appears to to be gravitationally bound in galaxies and clusters of galaxies, and as far as we can tell behaves like normal matter except it doesn't interact with light, and it could be a new type of elementary particle. Dark energy energy is much stranger. It's, it's the energy of empty space, and it's gravitationally repulsive. And we really don't know, you know, there are strange exotic possibilities, but them fit into the conventional picture of our, of our current physical theory very well, except an energy of empty space that is sort of there due to quantum mechanics. But even then the value is orders and orders of magnitude different than we would have predicted.

0:24:09 Lawrence: So dark energy is the greatest mystery in fundamental physics, and I think is going to require a lot longer to understand than dark matter.

0:24:18 Thomas: How much do we understand dark matter? Is it still a total mystery or is it, we understand a lot of the characteristics, but just not, okay.

0:24:26 Lawrence: Well, we don't. No, no, it's still a mystery. We have lots of candidates that are very good candidates for dark matter, and so therefore we understand lots of possibilities, but we have no idea which one of those possibilities will be manifest by nature.

0:24:39 Thomas: But dark energy, we're not quite even to that level of, I see.

0:24:42 Lawrence: It's an open question. It's, yeah, No, no. We had lots of ideas, but none of them are really well founded in fundamental physics, well,

0:24:50 Thomas: Roughly speaking, how was dark energy kind first proposed or discovered? Was it what was expanding our universe at even a larger rate than we first thought? Was that what it was?

0:25:01 Lawrence: Let's see, it was proposed in a variety of contexts. Einstein, in a way, proposed it without knowing he did, in the sense that he he pointed out that his theory could have a term which he called the cosmological term, and he he thought it'd be important but for the wrong reasons. We now understand that term would correspond to an energy of empty space, and the effect would be to now cause the universe to expand at ever faster. So that's been around for a long time.

The fact that it was likely to be that such a possibility was was actually could actually be manifest in the universe in which we live was was recognized a little bit later. And I'm happy to say that I was one of the people that posed that idea seriously in 1995, and argued that it was there, mostly to be heretical, to tell you the truth. But because it looked like something in order to explain the evidence that we saw in cosmology, you'd have to have such a term, and such a turn was so crazy I thought that clearly some of the data was wrong.

But I proposed it as a way to make the data consistent with some colleagues, it and and then three years later it was discovered to actually be there, and too much to the surprise of everyone, because no one believed that we said, but with the universe was it was discovered that the universe was expanding at an ever faster rate by a series of observers who were looking at distant galaxies and their speed away from us, by looking at objects called supernovae. They discovered that, remarkable, and it surprised them incredibly. And they won the Nobel Prize for that discovery.

0:26:27 Thomas: Wow. Yeah. You've talked about also in your book and other places, and I referenced it too, the emails you get of people telling you they figured it all out. I have to ask just for me, always I imagine that dark matter and dark energy must be a good, prime candidate for somebody to tell you, now here's what it's actually love. That's the truth or something like that. Do you get a lot of people telling you now they know what it is? There's the answer to physics deep questions somewhere in your inbox waiting to be read.

0:26:57 Lawrence: I get lots of answers every day, but most of them Tell me that we're wrong in everything we think. But I get lots of proposals, and many of them quite earnest ones, just saying, look, please tell me what I'm doing wrong, but others quite, um, confident that they've been working for for 20 years on their own theory, and and it really explains everything, and it's, it's one sense it's sad and unfortunate that that people, you know, because they're bound to be disappointed, but in another sense I just think it represents the fact that we all have these fundamental questions, and that's one of the reasons, as I say, why I write these books, so at least people can understand what the what the questions are and how how far we've come. And fortune favors the prepared mind, so there's a lot of bad intellectual baggage if you want to bring yourself up to the current level, and and and I, you know, I try and provide some of that for people.

0:27:00 Thomas: You know, that's A great point. That is exactly what this does for me. I can read this book and say, oh, wow, there are a whole lot of far more brilliant people than me working on this. It reminds me of when people think the counter argument to evolution is why are there still monkeys, as though, like, no scientist ever thought of that.

0:27:49 Lawrence: Yeah.

0:28:09 Lawrence: They don't really, exactly, I mean, it's not exactly, I've had people say that when I've tested the school board in Texas, and and the point is that's not how evolution works. It's, you know, we both have a common ancestor, but we did this, yeah.

0:28:13 Thomas: Yeah, yeah. Rooms full of biologists just, oh, guys, there's still monkeys. We forgot. Scrap it all. Scrap at all.

0:28:28 Lawrence: Yeah, exactly, oh, really, there's still monkeys, oh, we never realized that.

0:28:31 Thomas: Darn it. We forgot to plug that variable in. Back to the drawing board. But it's sort of that sort of thing where when you learn about or when I learn about, you know, you already know, but when I learned about just how complex and how amazing this process of putting together this picture of the universe is, I'm less apt to propose my pet theory of dark matter. Well,

0:28:32 Lawrence: Yeah. Yeah. Yeah. Well, Yeah, great, I mean, I think, but that shouldn't make you laugh, but it shouldn't making you wonder less, or or it, you know, what I hope it'll do is provoke new questions that are perhaps more appropriate to the universe, but, no, but maybe even more interesting.

0:29:09 Thomas: I've got a question for you. I don't think it's a new one, but I've got a questions. What is the difference between empty space and nothing? And maybe this relates to your last book a little more. But I've always wondered that. I mean, when you're talking about a universe from nothing or laws from nothing, whatever it is, is that different than empty space? Is it the Higgs field? Like nothing wouldn't have any sort of fields or anything, thing, but empty space does. Is that what it is?

0:29:12 Lawrence: You, Well, To, really, the answer is it depends what you mean by nothing, and I, one of the reasons I spend a lot of time in that book, you know, so, Nothing, talking about the different kinds of nothing, um, is because most people really don't think about it. When they say nothing, I mean, they don't really know what they mean by nothing.

For many people, empty space was nothing, in fact, the Bible, in some sense, the void was nothing, and and and that's that's one kind of nothing, but then having no space at all and is another kind of nothing.

And so it really depends what you mean, but for many people, you know, if you if you get rid of everything around you, give it all the particles of radiation, you know, that's what's in your hand, and you say nothing, um, but it turns out that that nothing is really not such, is really much more complicated than you imagine, it's actually got, it's a boiling brew of elementary particles that are popping in and out of existence, so we've changed the definitions of what many people think of as nothing, and that upsets some people, but but I call it learning.

0:30:27 Thomas: Yeah, yeah. I have loved thinking about this ever since reading your last book and seeing the lecture, actually, just trying to think about that. And is there a difference between, sorry if this language doesn't make sense, but is there a difference entre nothing as in like somewhere out in empty space? Sure, it looks like nothing, but as you said, there's maybe virtual particles, there is different stuff, vacuum energy, whatever whatever it is. And like a hypothetical nothing, I know it's a weird word, but outside of our universe. I don't know a better way to put that. Is there a difference between those two things? Is it a matter of theory? Do we not know? Or is that an unintelligible question?

0:31:03 Lawrence: Well, It's a question you can ask, but, again, you've got to be careful of what you mean. First of all, we don't know if there is anything outside of our universe, you don't, if there isn't any space or time in anything, or if our universe is unique, there could be other universes. And then, and then again, the question is, what do you mean by nothing outside of readers years, do you mean, uh, space that's empty that's expanding ever faster but has nothing in it, do you mean regions with different laws of physics, do you, or, or I, you know, so it really depends on how you ask the question, but the answer is that there really doesn't have to be anything outside, outside of our universe, uh, our universe could be unique, and and and space and time could have been created when our universe began, and our universe doesn't have to be embedded in anything bigger. Current ideas are that it probably is, but there's no requirement that that be the case.

0:31:40 Thomas: Interesting.

0:31:57 Thomas: I was actually going to ask you, pretty related to this, because your first book, A Universe from Nothing, I watched a lot of different talks and debates you had afterwards, and you did get a ton of people pushing back on that definition of nothing from actually lots of different groups, I would say, not just like religious people, but other people as well. I wanted to know, did anyone change your opinion on that, or make you rethink kind of the philosophy of what you were talking about, or was it a case of people just really wanting to hold on to their pet definition of what nothing is, and they weren't quite seeing scientifically what, what what it is.

0:32:37 Lawrence: Well, after that book came out, for example, as I began to confront these questions from people, I realized I had to refine my own way of expressing what I was trying to say. I think I did it clearly, but in the context of the issues and concerns they had.

And probably the most important thing is to say that when I'm talking about a universe of nothing, I was saying how amazing it is that you could get a universe of 100 billion galaxies with 100 billion stars from, from first of all, a universe that had none of that in it, and secondly, from no universe at all. Now, other people would say, but what if there were other universes, or there was something before a universe, or if you could define that question.

And I say, well, that that's fine, but that's not the question I'm asking, and you know, and and that may be, a you know, a vital concern to you, but the but, but that's not the issue I'm asking. To me, it's amazing that you could get a universe, our universe may not have existed, and make whether anything else existed is an interesting question, but it's a semantic one, and if that bothers you, you worry about that question, but but don't, but but the key question is, could you get, could, if our universe have come into existence without having been in existence before, and produced everything we see without any supernatural shenanigans, and we have a plausible story for how that could happen, and that's amazing. And, um, as far as the other questions, those are in maybe interesting philosophical ones, but they're not particularly productive at this point.

0:34:02 Thomas: Yeah. And the one thing I wonder, and a question I think you've gotten too is, well, you had to have some laws for that to happen to which I, yeah, I think you've said the laws could also come from nothing when that's the part I,

0:34:09 Lawrence: Maybe. Yeah. Well, Exactly. The law, of the laws of our universe could have come into existence when our universe came to existence. There could be an infinite number of physical laws that are possible, in which case that's equivalent, in my mind, having no laws at all. But the answer, and maybe the laws, maybe there is only unique set of laws of physics, but that doesn't obviate, you know, some people say, "Aha, but there were laws, you see, there wasn't nothing."

0:34:25 Thomas: Yeah, yeah.

0:34:34 Lawrence: I say, well, that's fine if that makes you happy, but I don't give a damn, um, because really the question is, our universe did not exist and then came into existence, that's a remarkable... to argue that somehow that minimizes that remarkable possibility, and the fact that we have a plausible explanation of that possibility is no less amazing, whether or not there's a unique set of laws of physics, or whether there's an infinite set of laws of physicists, and sort of hold your... to say, "Look, look, there are laws, therefore there's God," it's just such a ridiculous, you know, whenever you say "therefore there is God," it just is an example stopping thinking.

0:35:10 Thomas: Yeah, I totally agree. But I, but I do still, even though that's not where I'm coming from, I'm still, I, it's so hard to, to grasp that. So do you mean, yeah?

0:35:18 Lawrence: It's not easy. Question, I mean, it's my

0:35:20 Thomas: Yeah, yeah. Hey, well, I've got Lawrence Krauss here. I'm trying to try to find a way to grasp it.

0:35:26 Lawrence: Point is that it's not an easy question, and there are questions we don't have the answer to, but that's, there's no, problem not understanding is evidence of not understanding, it's just not of God. And so these are difficult questions, but the fact that we come as far as we have, the fact that we have a, that we can ask, you know, how could a universe be created from, from nothing, as I described, without it without any supernatural shenanigans, and what would be the properties of such a universe, and the fact that we, when we ask what would the universe that came from nothing look like, it looks just like it would look just like the universe in which we live, those are amazing discoveries and should be celebrated, and the fact that there's things we still don't understand is great, but, but it doesn't stop us from celebrating this remarkable progress that science has made. Yes.

0:35:35 Thomas: Sure.

0:36:09 Thomas: Absolutely. And that's something that I love that your book accomplishes. It really illustrates how amazing it is. Speaking of that universe that is difficult to comprehend, I've heard you ask before whether or not the universe is infinite. And I believe your answer there is usually that the best theory currently predicts it's not infinite, but what I'm wondering is how could there be, I'm sure there's an answer to this, but how could there be a big bang but then an infinite universe? That seems counterintuitive to me that it could start as a pinpoint and then go somehow all the way to infinity, or is that an incorrect picture of even what would be going on in that sense?

0:36:52 Lawrence: Um, it is.

0:36:52 Thomas: Usually, it usually is.

0:36:54 Lawrence: No, no. First of all, you know, well, let me say that you could imagine an infinite universe that's still at a Big Bang, because the universe could be infinite, but it could be infinitely dense at every point. So you could have a universe that simply big, that's infinitely dense and every point, and our observable universe rose from one of those points. But the vast universe was infinitely bigger. So so but so that's possible, although, as I say, so that certainly a logical possibility.

Our current picture is that that possibility is not likely, in the sense that we think that if you want to imagine a universe that came into existence by quantum fluctuation, then the ones we can easily imagine right now doing so are ones that are actually finite in spatial extent and then can grow forever, as our universe looks like it may do, do, and so while it's never infinitely big, it is constantly getting larger. And that there could be an infinite set of such universes.

So the current best picture is that our universe is probably not infinite in spatial extent. But that doesn't mean you couldn't have one, you certainly could, at least in principle. And

0:37:08 Thomas: Hmm. Okay.

0:38:03 Thomas: So does that, okay. So it kind of has to do with a little bit of the definition of the word universe. I guess then would the question be, yeah.

0:38:10 Lawrence: That's really important, by the way, our definition of the word universe has changed, um, in, as when I was growing up, universe was everything, and that was sort of a, you know, kind of vague definition, but we have a much more operational one now, which is, um, we define our universe to be that region of space with which we could have one day been in communication in the past, or could one day in the future be in communication, and, and namely of the locus of all points that we can have, that could have causally impacted upon us, or that we could cause the impact on in the future, and that's an operationally useful definition of universe.

0:38:16 Thomas: Okay, okay, so even though things are going to expand far beyond, as you've talked about, where we could detect or see, well not we, whoever's around, I guess, if anybody, that's still part of our universe because at one one time could have been in causal relation to them in some way.

0:38:55 Lawrence: Yeah. Yeah. Yeah. But there could be other regions which we never were in causal contact with, and which we ever will be, and, and, and those we would, it's reasonable to not sort of describe as part of our universe, but

0:39:12 Thomas: I've got to ask you a couple quick questions about string theory. First off, could you describe it just real quick in two minutes, describe all of it? No, just kidding. You've spoken about it in the past. I'm wondering if you could give a very quick rough definition for anyone who's not familiar with string theory? Okay.

0:39:22 Lawrence: I was going to say no. Well, the idea is that is that, um, is simply that on the smallest scales, what we think of as elementary particles are really excitations of more fundamental objects that have a string-like character. And when that idea was first looked at, the problem is that it didn't make mathematical sense unless you generally had more than four dimensions for those string-like excitations to live in. The string theory generally requires more direct dimensions. Originally it was 26, but then it's been reduced to 10 or 11, and maybe even different changes. But the theory has gotten more complex. And it's not really a theory. The mathematics has gotten more complex as it's realized that even strings are not the fundamental objects in this, in this picture. But the thing that made it exciting for many people in the 1980s is that you might be able to get a quantum theory of gravity in such a picture that was consistent, that made mathematical sense.

0:40:18 Lawrence: And that's why it's caused such interest among many physicists. Unfortunately, however, the theory has indeed become more complicated in mathematically. We're not even sure we understand the, we're actually pretty certain we don't understand all the details of it mathematically. And it's not clear that it relates to the universe in which we live. It's an interesting idea. And, and it has, it has had great potential originally, but it hasn't, it certainly hasn't fulfilled the potential that many people had hoped in the 1980s. That doesn't mean that one day it won't, but, but there's no evidence that, that it describes reality at this point. Well,

0:40:50 Thomas: So it's, it's pretty much just essentially math right now, it's like doing, uh, kind of math problems independently, and then maybe one day we find out.

0:40:59 Lawrence: Well motivated, well, well motivated mathematics and the, and the math that's resulted from string theory has allowed us to use new techniques to, in other, other areas of physics, to, it's given us new mathematical tools that have been very useful in various areas of physics, so it's not been useless, it just hasn't filled the grand expectations that were claimed in the 1980s, no.

0:41:00 Thomas: Okay. Hmm. Right. Right. But nothing has jumped out as, oh, this, this describes the real world, uh, you know, aha, we've, we've got a, okay. Is

0:41:24 Lawrence: There's interesting ideas related to black holes, but again nothing has yet jumped out and explained clearly. Well,

0:41:28 Thomas: Your money, if you, if you had to make a bet, if you were forced, uh, by God, to make it, is your, your money on, uh, string theory ever kind of reaching that status, or do you think that it

0:41:41 Lawrence: You know what, the great thing about physical theories is most of them are wrong, if they were, anyone to do physics, so if you, you pick any new theory, the, the likelihood is that it's wrong. So

0:41:46 Thomas: Yeah so that's the safe money, okay, I'm gonna put my money on that. So, I know you have to go, so I got, think one last question that hopefully will be a nice little ending to it. You, in this book, we've already mentioned and talked about, the stories you tell, a lot of great thinkers who have helped write this greatest story ever told, that, that you're telling in this book. I'm wondering, I'm not going to ask you like, who's the smartest person ever, but a sort of a version, a more refined version of that, I wondering if you have an answer to. If you could, if you were to guess on which great thinker in your opinion was like the least replaceable in your story, because sometimes you describe, you know, one or two people, maybe multiple people were on the verge of this theory and, or this discovery, and it would have, one guy didn't exist, the other person would have made the discovery, something like that.

0:42:38 Thomas: But I wonder if there's anybody that you would guess that is the least replaceable, like somebody who, if they weren't born, be it Newton or whoever, that would have set us back in our scientific understanding the most. Oh,

0:42:52 Lawrence: There are a number of people who've made huge, huge discoveries and had insights that put this forward, Newton was a clear example, or Galileo, you know, the standard suspects, Einstein and others, but to hypothetically say, what, you know, what would have happened if they hadn't been around, if physics is such that, that it doesn't depend on individuals, that it may take longer, longer, that, but eventually the experiments will, ultimately we think, lead us to insights when creative people are working on them, and, and that, and that, uh, and it's generally a collaborative enterprise, and so it's not just done by individuals. And so there are people who make great contributions, and I described them in the book, but I don't think anyone is indispensable, um, and what the world would have been like if they hadn't been around is the kind of hypothetical question that interests some, some people, but, but not me.

0:43:39 Thomas: Okay. Fair enough. I just wanted to get a little fun insight into who made the biggest, nothing rides on it or anything, but

0:43:42 Lawrence: I know. And I didn't mean to put down your question. No, no. I mean, and it's, it's not an unreasonable question, but there are to celebrate the discoveries of the people who have been, who made a contribution is what the book is all about. And, and there are, there are many people, not just the individual groups. And and I hope I reflect that the science is a collaborative enterprise, that there were lots of ideas that went back and forth and there were people added to them and it's a wonderful social experience and not just the work of people done alone in rooms in the middle of the night or something like that.

0:43:46 Thomas: Yeah.

0:44:13 Thomas: How big of a of misconception is that, is it the kind of thing where whoever's name ends up getting slapped on the Nobel Prize is kind of whoever the only person we remember, but there's a lot more. Yeah.

0:44:20 Lawrence: Exactly. Exactly. Which is which is certainly not the case. Yeah. Absolutely, it's

0:44:24 Thomas: Yeah, well, Lawrence Krauss, thank you so much for your time. Really a pleasure. This is, it's been a dream of mine to interview you. And I'm so glad I've gotten to speak with you. Really. Thank you.

0:44:35 Lawrence: Been a, it's been a pleasure. I look forward to it.

0:45:00 Thomas: Well, what a pleasure that was for me. I hope you guys enjoyed that interview as much as I enjoyed having it. Seriously, from my perspective, kind of a high point for my show. Just blown away, kind of starstruck. Literally. No, not literally. That would mean I was struck by a star. Still figuratively, but in two figurative senses. I'll get that figured out. In the meantime, have a good week until I see you again on Thursday. And thanks for listening. Thanks for supporting the show. By the way, supporters over on patreon.com/seriouspod got this episode early and I hope you enjoyed that, so that's just a benefit that you sometimes get when you sign up over there in addition to occasional bonus material, so check that out and I will see you guys on Thursday.